/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

#include "SecFetch.h"
#include "nsIHttpChannel.h"
#include "nsContentUtils.h"
#include "nsIRedirectHistoryEntry.h"
#include "nsIReferrerInfo.h"
#include "mozIThirdPartyUtil.h"
#include "nsMixedContentBlocker.h"
#include "nsNetUtil.h"
#include "mozilla/BasePrincipal.h"
#include "mozilla/StaticPrefs_dom.h"

// Helper function which maps an internal content policy type
// to the corresponding destination for the context of SecFetch.
nsCString MapInternalContentPolicyTypeToDest(nsContentPolicyType aType) {
  switch (aType) {
    case nsIContentPolicy::TYPE_OTHER:
      return "empty"_ns;
    case nsIContentPolicy::TYPE_INTERNAL_SCRIPT:
    case nsIContentPolicy::TYPE_INTERNAL_SCRIPT_PRELOAD:
    case nsIContentPolicy::TYPE_INTERNAL_MODULE:
    case nsIContentPolicy::TYPE_INTERNAL_MODULE_PRELOAD:
    case nsIContentPolicy::TYPE_INTERNAL_WORKER_IMPORT_SCRIPTS:
    case nsIContentPolicy::TYPE_INTERNAL_CHROMEUTILS_COMPILED_SCRIPT:
    case nsIContentPolicy::TYPE_INTERNAL_FRAME_MESSAGEMANAGER_SCRIPT:
    case nsIContentPolicy::TYPE_SCRIPT:
      return "script"_ns;
    case nsIContentPolicy::TYPE_INTERNAL_WORKER:
      return "worker"_ns;
    case nsIContentPolicy::TYPE_INTERNAL_SHARED_WORKER:
      return "sharedworker"_ns;
    case nsIContentPolicy::TYPE_INTERNAL_SERVICE_WORKER:
      return "serviceworker"_ns;
    case nsIContentPolicy::TYPE_INTERNAL_AUDIOWORKLET:
      return "audioworklet"_ns;
    case nsIContentPolicy::TYPE_INTERNAL_PAINTWORKLET:
      return "paintworklet"_ns;
    case nsIContentPolicy::TYPE_IMAGESET:
    case nsIContentPolicy::TYPE_INTERNAL_IMAGE:
    case nsIContentPolicy::TYPE_INTERNAL_IMAGE_PRELOAD:
    case nsIContentPolicy::TYPE_INTERNAL_IMAGE_FAVICON:
    case nsIContentPolicy::TYPE_IMAGE:
      return "image"_ns;
    case nsIContentPolicy::TYPE_STYLESHEET:
    case nsIContentPolicy::TYPE_INTERNAL_STYLESHEET:
    case nsIContentPolicy::TYPE_INTERNAL_STYLESHEET_PRELOAD:
      return "style"_ns;
    case nsIContentPolicy::TYPE_OBJECT:
    case nsIContentPolicy::TYPE_INTERNAL_OBJECT:
      return "object"_ns;
    case nsIContentPolicy::TYPE_INTERNAL_EMBED:
      return "embed"_ns;
    case nsIContentPolicy::TYPE_DOCUMENT:
      return "document"_ns;
    case nsIContentPolicy::TYPE_SUBDOCUMENT:
    case nsIContentPolicy::TYPE_INTERNAL_IFRAME:
      return "iframe"_ns;
    case nsIContentPolicy::TYPE_INTERNAL_FRAME:
      return "frame"_ns;
    case nsIContentPolicy::TYPE_PING:
      return "empty"_ns;
    case nsIContentPolicy::TYPE_XMLHTTPREQUEST:
    case nsIContentPolicy::TYPE_INTERNAL_XMLHTTPREQUEST:
      return "empty"_ns;
    case nsIContentPolicy::TYPE_INTERNAL_EVENTSOURCE:
      return "empty"_ns;
    case nsIContentPolicy::TYPE_OBJECT_SUBREQUEST:
      return "empty"_ns;
    case nsIContentPolicy::TYPE_DTD:
    case nsIContentPolicy::TYPE_INTERNAL_DTD:
    case nsIContentPolicy::TYPE_INTERNAL_FORCE_ALLOWED_DTD:
      return "empty"_ns;
    case nsIContentPolicy::TYPE_FONT:
    case nsIContentPolicy::TYPE_INTERNAL_FONT_PRELOAD:
    case nsIContentPolicy::TYPE_UA_FONT:
      return "font"_ns;
    case nsIContentPolicy::TYPE_MEDIA:
      return "empty"_ns;
    case nsIContentPolicy::TYPE_INTERNAL_AUDIO:
      return "audio"_ns;
    case nsIContentPolicy::TYPE_INTERNAL_VIDEO:
      return "video"_ns;
    case nsIContentPolicy::TYPE_INTERNAL_TRACK:
      return "track"_ns;
    case nsIContentPolicy::TYPE_WEBSOCKET:
      return "websocket"_ns;
    case nsIContentPolicy::TYPE_CSP_REPORT:
      return "report"_ns;
    case nsIContentPolicy::TYPE_XSLT:
      return "xslt"_ns;
    case nsIContentPolicy::TYPE_BEACON:
      return "empty"_ns;
    case nsIContentPolicy::TYPE_FETCH:
    case nsIContentPolicy::TYPE_INTERNAL_FETCH_PRELOAD:
      return "empty"_ns;
    case nsIContentPolicy::TYPE_WEB_MANIFEST:
      return "manifest"_ns;
    case nsIContentPolicy::TYPE_SAVEAS_DOWNLOAD:
      return "empty"_ns;
    case nsIContentPolicy::TYPE_SPECULATIVE:
      return "empty"_ns;
    case nsIContentPolicy::TYPE_PROXIED_WEBRTC_MEDIA:
      return "empty"_ns;
    case nsIContentPolicy::TYPE_INVALID:
      break;
      // Do not add default: so that compilers can catch the missing case.
  }

  MOZ_CRASH("Unhandled nsContentPolicyType value");
}

// Helper function to determine if a ExpandedPrincipal is of the same-origin as
// a URI in the sec-fetch context.
void IsExpandedPrincipalSameOrigin(
    nsCOMPtr<nsIExpandedPrincipal> aExpandedPrincipal, nsIURI* aURI,
    bool* aRes) {
  *aRes = false;
  for (const auto& principal : aExpandedPrincipal->AllowList()) {
    // Ignore extension principals to continue treating
    // "moz-extension:"-requests as not "same-origin".
    if (!mozilla::BasePrincipal::Cast(principal)->AddonPolicy()) {
      // A ExpandedPrincipal usually has at most one ContentPrincipal, so we can
      // check IsSameOrigin on it here and return early.
      mozilla::BasePrincipal::Cast(principal)->IsSameOrigin(aURI, aRes);
      return;
    }
  }
}

// Helper function to determine whether a request (including involved
// redirects) is same-origin in the context of SecFetch.
bool IsSameOrigin(nsIHttpChannel* aHTTPChannel) {
  nsCOMPtr<nsIURI> channelURI;
  NS_GetFinalChannelURI(aHTTPChannel, getter_AddRefs(channelURI));

  nsCOMPtr<nsILoadInfo> loadInfo = aHTTPChannel->LoadInfo();

  if (mozilla::BasePrincipal::Cast(loadInfo->TriggeringPrincipal())
          ->AddonPolicy()) {
    // If an extension triggered the load that has access to the URI then the
    // load is considered as same-origin.
    return mozilla::BasePrincipal::Cast(loadInfo->TriggeringPrincipal())
        ->AddonAllowsLoad(channelURI);
  }

  bool isSameOrigin = false;
  if (nsContentUtils::IsExpandedPrincipal(loadInfo->TriggeringPrincipal())) {
    nsCOMPtr<nsIExpandedPrincipal> ep =
        do_QueryInterface(loadInfo->TriggeringPrincipal());
    IsExpandedPrincipalSameOrigin(ep, channelURI, &isSameOrigin);
  } else {
    isSameOrigin = loadInfo->TriggeringPrincipal()->IsSameOrigin(channelURI);
  }

  // if the initial request is not same-origin, we can return here
  // because we already know it's not a same-origin request
  if (!isSameOrigin) {
    return false;
  }

  // let's further check all the hoops in the redirectChain to
  // ensure all involved redirects are same-origin
  nsCOMPtr<nsIPrincipal> redirectPrincipal;
  for (nsIRedirectHistoryEntry* entry : loadInfo->RedirectChain()) {
    entry->GetPrincipal(getter_AddRefs(redirectPrincipal));
    if (redirectPrincipal && !redirectPrincipal->IsSameOrigin(channelURI)) {
      return false;
    }
  }

  // must be a same-origin request
  return true;
}

// Helper function to determine whether a request (including involved
// redirects) is same-site in the context of SecFetch.
bool IsSameSite(nsIChannel* aHTTPChannel) {
  nsCOMPtr<mozIThirdPartyUtil> thirdPartyUtil =
      do_GetService(THIRDPARTYUTIL_CONTRACTID);
  if (!thirdPartyUtil) {
    return false;
  }

  nsAutoCString hostDomain;
  nsCOMPtr<nsILoadInfo> loadInfo = aHTTPChannel->LoadInfo();
  nsresult rv = loadInfo->TriggeringPrincipal()->GetBaseDomain(hostDomain);
  mozilla::Unused << NS_WARN_IF(NS_FAILED(rv));

  nsAutoCString channelDomain;
  nsCOMPtr<nsIURI> channelURI;
  NS_GetFinalChannelURI(aHTTPChannel, getter_AddRefs(channelURI));
  rv = thirdPartyUtil->GetBaseDomain(channelURI, channelDomain);
  mozilla::Unused << NS_WARN_IF(NS_FAILED(rv));

  // if the initial request is not same-site, or not https, we can
  // return here because we already know it's not a same-site request
  if (!hostDomain.Equals(channelDomain) ||
      (!loadInfo->TriggeringPrincipal()->SchemeIs("https") &&
       !nsMixedContentBlocker::IsPotentiallyTrustworthyLoopbackHost(
           hostDomain))) {
    return false;
  }

  // let's further check all the hoops in the redirectChain to
  // ensure all involved redirects are same-site and https
  nsCOMPtr<nsIPrincipal> redirectPrincipal;
  for (nsIRedirectHistoryEntry* entry : loadInfo->RedirectChain()) {
    entry->GetPrincipal(getter_AddRefs(redirectPrincipal));
    if (redirectPrincipal) {
      redirectPrincipal->GetBaseDomain(hostDomain);
      if (!hostDomain.Equals(channelDomain) ||
          !redirectPrincipal->SchemeIs("https")) {
        return false;
      }
    }
  }

  // must be a same-site request
  return true;
}

// Helper function to determine whether a request was triggered
// by the end user in the context of SecFetch.
bool IsUserTriggeredForSecFetchSite(nsIHttpChannel* aHTTPChannel) {
  /*
   * The goal is to distinguish between "webby" navigations that are controlled
   * by a given website (e.g. links, the window.location setter,form
   * submissions, etc.), and those that are not (e.g. user interaction with a
   * user agent’s address bar, bookmarks, etc).
   */
  nsCOMPtr<nsILoadInfo> loadInfo = aHTTPChannel->LoadInfo();
  ExtContentPolicyType contentType = loadInfo->GetExternalContentPolicyType();

  // A request issued by the browser is always user initiated.
  if (loadInfo->TriggeringPrincipal()->IsSystemPrincipal() &&
      contentType == ExtContentPolicy::TYPE_OTHER) {
    return true;
  }

  // only requests wich result in type "document" are subject to
  // user initiated actions in the context of SecFetch.
  if (contentType != ExtContentPolicy::TYPE_DOCUMENT &&
      contentType != ExtContentPolicy::TYPE_SUBDOCUMENT) {
    return false;
  }

  // The load is considered user triggered if it was triggered by an external
  // application.
  if (loadInfo->GetLoadTriggeredFromExternal()) {
    return true;
  }

  // sec-fetch-site can only be user triggered if the load was user triggered.
  if (!loadInfo->GetHasValidUserGestureActivation()) {
    return false;
  }

  // We can assert that the navigation must be "webby" if the load was triggered
  // by a meta refresh. See also Bug 1647128.
  if (loadInfo->GetIsMetaRefresh()) {
    return false;
  }

  // All web requests have a valid "original" referrer set in the
  // ReferrerInfo which we can use to determine whether a request
  // was triggered by a user or not.
  nsCOMPtr<nsIReferrerInfo> referrerInfo = aHTTPChannel->GetReferrerInfo();
  if (referrerInfo) {
    nsCOMPtr<nsIURI> originalReferrer;
    referrerInfo->GetOriginalReferrer(getter_AddRefs(originalReferrer));
    if (originalReferrer) {
      return false;
    }
  }

  return true;
}

void mozilla::dom::SecFetch::AddSecFetchDest(nsIHttpChannel* aHTTPChannel) {
  nsCOMPtr<nsILoadInfo> loadInfo = aHTTPChannel->LoadInfo();
  nsContentPolicyType contentType = loadInfo->InternalContentPolicyType();
  nsCString dest = MapInternalContentPolicyTypeToDest(contentType);

  nsresult rv =
      aHTTPChannel->SetRequestHeader("Sec-Fetch-Dest"_ns, dest, false);
  mozilla::Unused << NS_WARN_IF(NS_FAILED(rv));
}

void mozilla::dom::SecFetch::AddSecFetchMode(nsIHttpChannel* aHTTPChannel) {
  nsAutoCString mode("no-cors");

  nsCOMPtr<nsILoadInfo> loadInfo = aHTTPChannel->LoadInfo();
  uint32_t securityMode = loadInfo->GetSecurityMode();
  ExtContentPolicyType externalType = loadInfo->GetExternalContentPolicyType();

  if (securityMode ==
          nsILoadInfo::SEC_REQUIRE_SAME_ORIGIN_INHERITS_SEC_CONTEXT ||
      securityMode == nsILoadInfo::SEC_REQUIRE_SAME_ORIGIN_DATA_IS_BLOCKED) {
    mode = "same-origin"_ns;
  } else if (securityMode ==
             nsILoadInfo::SEC_REQUIRE_CORS_INHERITS_SEC_CONTEXT) {
    mode = "cors"_ns;
  } else {
    // If it's not one of the security modes above, then we ensure it's
    // at least one of the others defined in nsILoadInfo
    MOZ_ASSERT(
        securityMode ==
                nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_INHERITS_SEC_CONTEXT ||
            securityMode ==
                nsILoadInfo::SEC_ALLOW_CROSS_ORIGIN_SEC_CONTEXT_IS_NULL,
        "unhandled security mode");
  }

  if (externalType == ExtContentPolicy::TYPE_DOCUMENT ||
      externalType == ExtContentPolicy::TYPE_SUBDOCUMENT ||
      externalType == ExtContentPolicy::TYPE_OBJECT) {
    mode = "navigate"_ns;
  } else if (externalType == ExtContentPolicy::TYPE_WEBSOCKET) {
    mode = "websocket"_ns;
  }

  nsresult rv =
      aHTTPChannel->SetRequestHeader("Sec-Fetch-Mode"_ns, mode, false);
  mozilla::Unused << NS_WARN_IF(NS_FAILED(rv));
}

void mozilla::dom::SecFetch::AddSecFetchSite(nsIHttpChannel* aHTTPChannel) {
  nsAutoCString site("same-origin");

  bool isSameOrigin = IsSameOrigin(aHTTPChannel);
  if (!isSameOrigin) {
    bool isSameSite = IsSameSite(aHTTPChannel);
    if (isSameSite) {
      site = "same-site"_ns;
    } else {
      site = "cross-site"_ns;
    }
  }

  if (IsUserTriggeredForSecFetchSite(aHTTPChannel)) {
    site = "none"_ns;
  }

  nsresult rv =
      aHTTPChannel->SetRequestHeader("Sec-Fetch-Site"_ns, site, false);
  mozilla::Unused << NS_WARN_IF(NS_FAILED(rv));
}

void mozilla::dom::SecFetch::AddSecFetchUser(nsIHttpChannel* aHTTPChannel) {
  nsCOMPtr<nsILoadInfo> loadInfo = aHTTPChannel->LoadInfo();
  ExtContentPolicyType externalType = loadInfo->GetExternalContentPolicyType();

  // sec-fetch-user only applies to loads of type document or subdocument
  if (externalType != ExtContentPolicy::TYPE_DOCUMENT &&
      externalType != ExtContentPolicy::TYPE_SUBDOCUMENT) {
    return;
  }

  // sec-fetch-user only applies if the request is user triggered.
  // requests triggered by an external application are considerd user triggered.
  if (!loadInfo->GetLoadTriggeredFromExternal() &&
      !loadInfo->GetHasValidUserGestureActivation()) {
    return;
  }

  nsAutoCString user("?1");
  nsresult rv =
      aHTTPChannel->SetRequestHeader("Sec-Fetch-User"_ns, user, false);
  mozilla::Unused << NS_WARN_IF(NS_FAILED(rv));
}

void mozilla::dom::SecFetch::AddSecFetchHeader(nsIHttpChannel* aHTTPChannel) {
  // if sec-fetch-* is prefed off, then there is nothing to do
  if (!StaticPrefs::dom_security_secFetch_enabled()) {
    return;
  }

  nsCOMPtr<nsIURI> uri;
  nsresult rv = aHTTPChannel->GetURI(getter_AddRefs(uri));
  if (NS_WARN_IF(NS_FAILED(rv))) {
    return;
  }

  // if we are not dealing with a potentially trustworthy URL, then
  // there is nothing to do here
  if (!nsMixedContentBlocker::IsPotentiallyTrustworthyOrigin(uri)) {
    return;
  }

  AddSecFetchDest(aHTTPChannel);
  AddSecFetchMode(aHTTPChannel);
  AddSecFetchSite(aHTTPChannel);
  AddSecFetchUser(aHTTPChannel);
}